Chaparral Yucca Seeds, and a Guest

My last post was about Chaparral Yucca, which is blooming in the Santa Monica Mountains right now.  A  few days after writing the post I was exploring Red Rocks Park in Topanga.  This park takes its name from the sculpted sandstone outcrops that rise from the Santa Monica Mountains.

Wind and water sculpted sandstone ledges

Wind and water sculpted sandstone ledges

Like most of the Santa Monica Mountains, this is a dry area, but it is relatively low elevation and nestled in a canyon, the bottom of which has an infrequently running stream and some lovely oak and sycamore trees.

The side slopes are home to the usual assortment of coastal chaparral plants, but the relatively low elevation, slightly greater water supply, and marginally cooler temperatures means that the plants are on an ever-so-slightly different flowering cycle.

Down here some of the Chaparral Yucca (Hesperoyucca whipplei) is still blooming, but other plants are well into the seed setting stage.

Chaparral Yucca seed pods slowly ripening

Chaparral Yucca seed pods slowly ripening

Each of the thorn-like stubs on the branches was a flower.  As you can seen a small percent of the flowers survive to form seed pods.  This year, this is a good crop, in other, wetter, years more might make to this stage.

The pods look like the offspring of a pickle and a ping-pong ball.  Green and slightly warty, divided into three chambers and about the size of a comfortable throwing stone.

Chaparral Yucca seed pod close-up

Chaparral Yucca seed pod close-up

As with the flowers, reaching them is a bit tricky because the basal rosette is composed of lance-shaped leaves crowned with needle tips.  Tips that only seem more aggressive and more prone to break off in your legs as the leaves dry in the increasingly hot summer sun.

Gathering these seed pods was an important activity for many of the coastal tribes as the seeds are edible and nutritious, and unlike the flowers and stalk, the dried seeds can be stored for a long time either whole or ground into flour.

At the moment the seeds are not-yet dried, but are still edible and tasty.

Chaparral Yucca seedpod cross-section

Chaparral Yucca seedpod cross-section

The seeds are flat and black or dark brown, and the capsules look very much like iris or lily seed capsules.  When fully ripe and dry the capsule splits open, disgorging the disk-like winged seeds that flutter to the ground in the frequent coastal breeze.

The green portion of the pod is extremely bitter, so it is best to separate the seeds from the pods for consumption.

The remains of the pods can last for several years in the dry climate.  They look a little like small loofahs hanging on to the dessicated flower stalks.

Chaparral Yucca dried seed pod

Chaparral Yucca dried seed pod

Chaparral Yucca grows in exposed areas in defiance of the sun and shallow soils.  This year even these hardy plants have few blooms and many of the other flowering plants here either didn’t bloom or did so quickly and finished quickly.  Despite the harsh conditions of this year, in some of the darker, damper areas a few plants still show their flowers.

In a little gully, well off the trails, I came across several blooming Scarlet Larkspur (Delphinium cardinale) plants.

Scarlet Larkspur (Delphinium cardinale) still blooming in a shady spot

Scarlet Larkspur (Delphinium cardinale) still blooming in a shady spot

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Chaparral Yucca, Spanish Bayonet – the many named Hesperoyucca whipplei

Despite the cool breeze blowing off the Pacific visible 1300 feet below (400 meters) and four and a half miles away (7 kilometers), it is hot.  Blisteringly so.  The sun beats down on me heating my skin like the bank of coals left over from a bonfire.  Across the valleys the slopes of the Santa Monica mountains waver in my vision as the rising heat warps the air, changing its density and bending the light.  At my feet what looks like heat shadows dance, but upon closer investigation I realize that it is a 6 inch (15cm) layer of extremely fine alkaline dust blowing over the trail like a Martian sandstorm seen from orbit.

This is one of the most diverse areas of California for birds, but all I hear is a single crow cawing as it glides over the ridge and falls into the canyon to the west of me.  Dressed all in black, even the crows must be broiling.  Here and there fence lizards and side blotch lizards scurry abruptly across patches of orangey dust leaving sharp trails in the fine powder that flies up from beneath their feet and whip-lashing tails.

Only the flies and ants are active; green bottle flies, landing to steal a lick of sweat from my arms before I shoe them away and inexhaustible armies of red ants collecting seeds to add to their larders.

It is the middle of the day, the time when the Chumash sun god grows weary of carrying the heavy bark torch he carries across the sky and stoops under its weight, allowing the flame to fall close the the planet’s surface.

Here and there on the drably greenish slopes pillars of bright white stand proud, like blowtorches, clearly visible for great distances in the bright sunlight.

Chaparral Yucca (Hesperoyucca whipplei) 3/4 of a mile away through a 300mm lens, uncropped.

Chaparral Yucca (Hesperoyucca whipplei) 3/4 of a mile away through a 300mm lens (8.5 zoom equivalent), uncropped.

These 9+ foot (3+ meter) beacons are the  inflorescences of an iconic coastal chaparral plant and the reason why I am walking in heat that even the lizards are avoiding.

This plant has a number of common names and has recently been reclassified and renamed in the academic literature.  The most common name is simply “yucca”, with the “y” portion pronounced as in “ya-all” rather than “you”.  This is not to be confused with “yuca” (pronounced with the “you” sound), the cassava root, a common food found through much of the tropics.

This particular species of yucca is also known as Chaparral Yucca, Common Yucca, Foothill Yucca, Our Lord’s Candle, Quixote Yucca, and, perhaps the most telling, Spanish Bayonet.  I find the latter name to be particularity evocative as the long, lance-like leaves are crowned with a needle-like point that easily penetrates clothing, only to break off under your skin, leaving a mark that itches for days to weeks as your body works the barb back out.

Like many organisms, this plant has been classified and reclassified, the scientific name changing back and forth as new information comes to light.  It is currently known as Hesperoyucca whipplei, a name coined in 1892 by Georg Engelmann, but it spent many years happily living under the name Yucca whipplei, when it was thought to be more closely related to Joshua Trees than recent genetic analysis indicates that it is.  Perhaps I am lazy, but I have always referred to it as yucca, and will continue to do so, relying on context to clarify which of several I mean.

The inflorescence of Chaparral Yucca is a mighty affair, that stands high above the landscape in defiance of herbivorous predators, protected by its height and the spiky ball of needle-tipped blades below.

Unopened buds at the opt ad a yucca flower stalk

Flowers and unopened buds at the top of a yucca flower stalk

A senescent yucca with a 4 foot (3+ meter) ball of blades dying after blooming)

A senescent yucca with a 4 or 5 foot (1-2 meter) ball of blades dying after blooming)

For many years these yuccas, which are monocots (having simple leaves with no branch-like structures in them) were though to be in the lily family (Liliaceae) on the basis of their flower construction which closely mirrors the multiple sets of 3  and superior ovaries that are a characteristic of lilies.  Now the yuccas have been moved into the Asparagaceae family which includes asparagus, orchids, hyacinths, Lily-of-the-Valley, and the close relative agave, known to most people in its cooked, fermented, and distilled form, Tequila.

Superior ovaries and the parts in sets of 3 and 6

Superior ovaries and the parts in sets of 3 and 6 – this flower had fallen onto a different plant

When you look at the flowers of a plant you are looking at its genitals, a thought that should give one pause the next time you buy flowers for your partner.  Unlike animals, plants cannot wander about to seek their mates and thus many must rely upon intermediaries for reproduction.  The various colors, shapes, scents, and sizes of flowers are meant to attract very specific sexual intermediaries.  Brightly colored flowers are often attractants for birds, butterflies, and bees that are active during the day, long tube-shaped flowers attract hummingbirds and insects with long tongues, flowers with fetid scents often attract flies and beetles.  The yucca has relatively large bright white flowers with a slightly sweet, nutty smell.

Bright white yucca flowers - white flowers often attract night flying animals such as moths and bats

Bright white yucca flowers – white flowers often attract night flying animals such as moths and bats

These highly scented, bright white flowers, so visible during the day, are meant to attract night flying creatures.  In this case a very specific moth, the California Yucca Moth (Tegeticula maculata).  The relationship between the Yucca Moth and the yucca plant is one of mutual dependence; despite all the other insects that come to steal nectar, only the yucca moth pollinates the plant.  As it does so, it deposits its eggs in the developing seed pods, where the larvae grow, eating some of the seeds as they grow.  These moths only lay eggs in the yucca seed capsules.  In return for pollination (sex) the plant sacrifices some of its seeds.  At this point, neither the plant, nor the moth can survive without the other.  The specificity of the relationship suggest that it is an old one.

The yucca plant is incredibly useful.  The long leaves are tough and full of strong fibers.  The whole leaves were woven into mats and sandals.  The fibers were separated and twisted into extremely strong cord; numerous time I have done this quickly in the field when I need a length of twine and do not want to cut the cord I carry in my pocket.  The flower stalk is full of water and sugar, the flowers themselves are edible, more than edible, they are delicious with a delicate nut-like flavor with a touch of bitterness, a little like cashew blended with bitter almond topped with a dash of gardenia scent.  The unripe seeds are edible raw or roasted, and the dried seeds can be ground into flour.

It is not only humans that find the plants useful and delicious, deer, rats and birds all like to eat the tasty bits, many getting water in addition to nutrients.

Yucca inflorescence being browsed on by a hungry animal

Yucca inflorescence after being browsed on by a hungry animal

It takes a yucca plant 4-6 years to reach flowering stage, then, like a century plant, it dies shortly after flowering.  Even while it is flowering the leaves begin turning color.

Yucca basal rosette with leaves dying after plant flowers

Yucca basal rosette with leaves dying after plant flowers

New plants grow from runners and dispersed seeds.

The old flower stalks can remain standing for another year or two before collapsing, often with the shredded remains of the seed pods still attached.

Fallen flower stalk with empty seed pods attached

Fallen flower stalk with empty seed pods attached

This is one of the iconic plants of the coastal chaparral environment, one which I admire, but treat with the utmost respect, having spent far too much time digging leaf-spikes out of my legs and arms over the years.

How Does the Acorn Get from Here to There? – Scrub Jays and Oak Trees

With a few exceptions trees in the Oak genus (Quercus) are easily, if not immediately, recognizable.  There are approximately 600 species in the genus divided into two sub-genera.  Oaks are found in North and South America, Europe, North Africa, and Asia.  The oaks in Asia are in the sub-genera, the Ring-Cupped Oaks (Cyclobalanopsis), whereas oaks in the rest of the world are members of the Quercus sub-genera.

Oaks have complicated relationships with a number of other species ranging from symbiotic fungus to parasitic wasps to humans.  Oaks feature in our mythology, we use the bark of Quercus suber, Cork Oak, to make stoppers for wine and for soft flooring, we make furniture and barrels from some species of oak, we made cart and early car axles from particularity strong species, they make excellent firewood, and they are fun to climb.

Climbing a Coast Live Oak (Quercus agrifolia) when I was little

Oaks also make acorns.  Sometimes, particularly when mast fruiting, oaks produce enormous quantities of acorns.  Most of these acorns are eaten by animals; insects, humans, pigs, squirrels, birds, and a host of other animals.  The survival and reseeding rate for acorns is low, but oak trees tend to be long-lived, some reaching ages of 500 years or more.  In the absence of other factors this low seedling success rate is not an issue as the tree produces thousands of acorns each year for hundreds of years.  Some seeds are bound to survive and turn into new trees.

Oaks have a particular problem.  Their seeds (acorns) are large.

Coast Live Oak (Quercus agrifolia) acorns

By themselves the trees can only drop the acorns under their own drip-line, in the shade where they will not sprout.  How does the tree send its seeds to a new place where they can sprout and are not left in a dense mat of easily found and eaten food?

Plants, being clever and manipulative in their slow vegetative manner, have all manner of methods for getting animals to carry their seeds far and wide.  Oaks harness many species to do this work, bribing them with the highly nutritious seeds they produce.  Across much of North America scrub and blue jays are put to work distributing acorns across the landscape.

Western Scrub Jay (Aphelocoma californica) in the Santa Monica Mountains – possibly Belding’s Scrub Jay (Aphelocoma californica obscura)

Meet the Western Scrub Jay (Aphelocoma californica), also known as the California Scrub Jay, and sometimes known as, “That damned bird!”  It is a mid-sized bird, perhaps a foot long including tail, loud, strong, clever, and imperious.  Like all jays it is in the Crow family (Corvidae), one of, if not the, smartest of bird types.  Corvids are renowned for their problem solving abilities and feats of memorization.  Scrub jays are no exception.

When the acorns are ripe jays congregate on the trees, grab as many acorns as they can, and fly off to stash them for future use.

Scrub Jay carrying acorns to hide for lean times

Each bird seems able to carry 3 or 4 acorns at a time, in the picture above there are two in the jay’s beak and at least one more in its crop.

Jays will carry acorns up to a mile and a half, hiding them in widely distributed caches of 1-3 acorns per cache.  The bird memorizes the locations of each cache, that of any other caches it sees other birds store, and will move its own caches if it knows it has been observed making its own cache.  Some of these caches will be forgotten and in some of those the seeds will sprout.

One bird doesn’t seem like it would make much of an impact, but one must recognize both the diligence of each bird and the number of birds engaged in this activity.

Scrub Jays harvesting acorns (@ 40 photographs taken over @ 10 minutes)

The photo above is a compilation of about 40 photographs taken over roughly 10 minutes.  This level of activity has been constant on this tree throughout the day over the past 2 or 3 weeks.  The scale of the endeavor starts to become apparent.  Beneath the tree ground squirrels and gray squirrels gather seeds from the ground to add to their own larders as well.

The oak tree has effectively expanded its dispersal distance from a few feet to over a mile.  Not only that, the oak tree has found a way to have its seeds hidden in safe locations and planted in the ground.  Only a small proportion of the acorns will survive to make new trees, but over the 350 year expected life-span of this particular tree it is not unreasonable that several hundred acorns will survive to produce trees that will live long enough to produce seeds of their own.

Scrub Jay enjoying the sun

+++ Cathy commented that any discussion of oak trees in California is incomplete if Acorn Woodpeckers (Melanerpes formicivorus) are not included.  They don’t live where I am at the moment, but last week I was up in my old stomping grounds and visited one of my favorite grainery trees.  Grainery trees are where these communal woodpeckers store and dry their collected acorns.  This particular tree is an ancient, wind-blasted Douglas Fir atop Mt Tamalpais, has a nearly 4 foot diameter, has been lightening struck numerous times, and sits amidst a copse of large moss enshrouded oak trees.

Old grainery trees will be used by many generations of these little woodpeckers and the trees look like an art project .

In any event, here is a photo of part of a grainery.+++

Acorn Woodpeckers (Melanerpes formicivorus) use all surfaces of a tree to make their larders. They will use fence-posts and the sides of barns as well.

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As a final note, in many areas, but in California in particular, oaks of all species are severely imperiled.  Oak woodlands are often considered to be the most important ecosystem in the region, but they have been subject to a number of stresses.  Oaks have been extensively cleared for orchards, vineyards, farmland, and urban use.  Saplings are eaten by cattle in range-lands, non-native feral pigs sniff out and eat all the acorns they can find, sometimes damaging tree roots in the process, and an ill-considered introduction of turkeys to the state by Fish & Wildlife to raise hunting revenue has led to even more acorns consumed by these overly prolific birds.

On top of all this, Phytophthora ramorum, a pathogen in the fungus-like family of water-molds, was accidentally introduced to the state via exotic ornamental plants and is causing wide-spread devastation.  This is commonly called Sudden Oak Death Syndrome and foresters strongly recommend not transporting oak firewood and washing cutting tools and boots when moving between oak growing regions.

Chamise – a key chaparral plant

The chaparral ecosystem in California is comprised of a dense and diverse collection of small to mid-sized woody shrubs.   It covers the hills in a shallow cloak of gray-green vegetation just thick enough to soften the contours of the land, but not to hide them.  In some places the chaparral is dense and thick, so much so that it is nearly impossible to penetrate it, other places it is sparse and low.  Animal trails riddle the chaparral and the bones of the land show through with a dramatic abruptness.

Sandstone outcrops above a chaparral covered hillside at Red Rocks State Park in Topanga

Chaparral grows primarily in dry, hot areas, as such the plants have a number of moisture saving adaptations that are most easily seen in their leaves which tend to be either small or waxy, or both in many cases.  The ecosystem is surprisngly diverse in both plants and animals, but despite this there are a small handful that are common from Mexico through most of California and that, taken together, could be considered to be the background matrix of chaparral plants.  Sage (Artemisia) and Ceanothus both are broad genus level plants with many individual members.

These plants are common in the chaparral, and taken with another extremely common plant, Chamise (Adenostoma fasciculatum), comprise what I think of as the matrix plants for the California wide chaparral.

Chamise (Adenostoma fasciculatum) flowers are small and clustered in tight bundles at the tips of the branches

Chamise, also known as greasewood, is in the rose family and produces clusters of small white flowers that look much like another rose family genus, Spiraea, which includes hardhack and meadowsweet.  The flowers set seed and dry on the branch, remaining affixed to the stalk for several seasons after blooming.

The leaves of Chamise are needle-like, clustered in little bundles called fascicles, the word the scientific name derives from.  On the whole, the plant looks something like a cross between rosemary and juniper with shredding bark, gnarled limbs, and and regularly placed leaf clusters.

Old Chamise plant on a ridge in the Santa Monica Mountains

Like many chaparral plants Chamise seeds require fire to germinate.  This ensures that the seedlings will be able to take advantage of the temporary increase of nutrients and open sunlight in the plant’s early stages of growth.  Estimates of the longevity of Chamise vary, but range from 100-200 years.

Chamise is not generally considered to be good browse for animals, but it is common to find extensive patches of heavily browsed plants.  In some places the browse is so heavy that the bushes look like sculpted hedges, in other places they look like carefully trimmed bonsai trees.

Browsed Chamise branches

When it has not been browsed Chamise produces a relatively dense growth of vertical shoots.  Over time many of these will die, with the dead stalks being retained by the plant.  Some estimates of the total volume of retained deadwood on old plants reaches 60-70%, greatly adding to the potential combustibility of the Chamise.

Young Chamise branches

California Buckwheat (Eriogonum fasciculatum) can sometimes be mistaken for Chamise by the casual eye, but the leaves are broader and flatter and the flower structure is very different.

California Buckwheat (Eriogonum fasciculatum)

Chamise is found primarily in California, though northwest Mexico and western Nevada also host populations of this plant.  Within California it is found in nearly all of the chaparral habitats as is shown on the digital Jepson Herbaria hosted by UC Berkeley.

Chaparral types with Chamise

This is a tough plant.  It grows with little water, on hard, rocky soil, and can even grow in serpentine soils, a soil type that kills many plants.  Many people do not like Chamise due to its flammability, but it is an excellent erosion control plant, provides cover for a number of birds and small animals, and serves as a last resort browse as well.

It is not the only chaparral plant by any stretch, nor even the most typical in any given area, but it is the one I have seen in the most places through California.

A Brief Stopover in the Santa Monica Mountains

I am back on the West Coast of the US for a few weeks before I fly off into tomorrow sometime in November.  The specific part of the west coast I am in is the Santa Monica Mountains, a rugged stretch of steep sided hills perched over the Pacific Ocean covered with blanket of dense chaparral.

Evening sunbeams in Topanga

The precipitous, heavily weathered mountain slopes are eroding from ancient sea-floor uplifted and broken by geologic stresses, frequently manifesting in the form of earthquakes.  The region is dry, though fog is common and periodic rainstorms can quickly drench the area, causing local flooding and landslides.  The dusty ground is colored a dull orange/tan with angular, flat, broken pebbles peeling out of shallow, soft bedrock with occasional anemonite and bivalve fossils.  Under the twelve foot chaparral canopy the gritty soil is overlain by several inches of slowly decomposing leaf-litter and twigs, loose in some places, held together by dense mycelial mats in other places, particularly under the scrub and live oaks.

Infrequent damp, cool places are home to massive coastal live oak (Quercus agrifolia) and California sycamore (Platanus racemosa) while a bewildering variety of woody shrubs make up the body of the chaparral cloaking the rest of the mountains.  Here and there small meadows, potreros in the southern California vernacular, and wind-blasted rock outcrops break up the gray/green vegetation.

Lemonade Berry (Rhus integrifolia) flower buds

Chamise, Toyon, Scrub Oak, Lemonade Berry, Ceanothus, Yucca, and various sages make up much of the more common large shrubs with Black Walnut, Elderberry, Coastal Live Oak, and California Sycamore making up the primary larger trees.  The softer vegetative plants of the understory tend be short-lived, only appearing to bloom and set seed after the rain.

The thick, leathery leaves of the Lemonade Berry (Rhus integrifolia) in the image above are fairly typical of chaparral plants in that they are mostly evergreen and have evolved to husband moisture.  Some plants steal their nutrients from other plants, Dodder (Cuscuta californica) is common in the chaparral, some years blanketing their hosts with yellow-orange leafless vines sporting nearly invisible flowers.

Dodder (Cuscuta californica) on Lemonade Berry. Dodder is most active after rains.

For such a dry region the diversity of both plant and animal life is astounding.  The most obvious animal life during the day are the birds.  Birds of all sizes everywhere, year round.  Little tiny acrobatic birds such as the Bushtit traveling in small noisy flocks.

Bushtit (Psaltriparus minimus) on scrub oak

Large birds of prey soaring overhead in search of thermals or their next meal.

Red-Tailed Hawk (Buteo jamaicensis) riding the wind

Meadowlarks, finches, wrens, thrashers, scrub jays, woodpeckers, hummingbirds quail, and a host of other birds flit about within earshot, if not within eyesight.

Western Meadowlark (Sturnella neglecta) atop a Toyon (Heteromeles arbutifolia) shrub, a popular food bush for many birds. Toyon is also known as Hollywood, the plant Hollywood owes its name to.

Anna’s Hummingbird (Calypte anna) perched on a non-native Tobacco Tree (Nicotiana glauca)

Mammals abound as well.  Small rabbits scatter like frogs in a pond in the evenings, and in the mornings I find fresh coyote, fox, bobcat, skunk, raccoon, deer, and mountain lion tracks on the unused dirt roads.  In the potreros badgers are not uncommon, large woodrat piles abound, bats fly through the canyons in the evening, and ground squirrels are everywhere.  Sometimes, if you have a quiet foot, a lot of patience, and good deal of luck you sneak up on these animals.  A few years back I was out here and found a coyote sleeping in the sunlight.

Coyote (canis latrans) sleeping in the sunlight

This being a dry area there are numerous lizards and snakes, mostly hidden from sight, and insects of all sorts.

I prefer wet places, places that stay green, but I do appreciate and enjoy the diversity of life here in the steep chaparral.  It is strange to be here between damp New England and my next home in Borneo where I will receive 3-4 meters of rain a year.

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Some of these photos are taken with a Nikon D80, some with a Nikon D90, and several with a Nikon D600.  I am still learning the latter camera, but if any of you out there are debating buying the D600, I can honestly say I recommend it.  The Meadowlark and Hummingbird images were taken with the D600 and are cropped from much larger images.